A spur is a narrowband interference signal characterized by high spectral content at a single frequency known as a spur frequency. Spurs may originate locally at a device, e.g., harmonics of a reference oscillator for a transmitter or receiver, harmonics of clocks used for digital circuits in the device, mixing products of RF components, etc. Spurs may also originate from sources external to the device itself. Unmitigated, spurs may lead to unwanted effects such as stray signal emissions by a transmitter, as well as corruption of signals received by a receiver.
Techniques for suppressing spurs include passing a signal containing both the desired signal and the spurs through one or more notch filters designed to suppress spectral content at predetermined spur frequencies. Such techniques are described in, e.g., U.S. patent application Ser. No. 11/324,858, “Spur suppression for a receiver in a wireless communication system,” filed Jan. 4, 2006, assigned to the assignee of the present application, the contents of which are hereby incorporated herein.
It would be desirable to provide further techniques for suppressing spurs, as well as for identifying spur frequencies and tracking them over time.